The present invention relates to an impact armature for solenoid devices.
The armature of prior-art solenoid devices such as, e.g., solenoid valves, has to overcome two forces when the latter is actuated: the force of a spring that tends to keep the armature in its normal position of rest, whether N.O. (normally open) or N.C. (normally closed), and the force of the pressurized medium that is handled by the valve. These forces act in the same direction and, therefore, add up. As the magnetic force acting on the armature diminishes with the square of the width of the air gap between the armature and the pole of the solenoid, it is often difficult to arrive at a satisfactory compromise between the need for a substantial gap width which is one of the parameters determining valve throughput, and the coil ampere-turns which determine the size, cost and power consumption of the solenoid valve.
It is one of the objectives of the present invention to provide a solenoid device which, compared to prior-art devices of the same type, may either have a larger gap width for the same number of ampere-turns, or the same gap width with fewer ampere-turns than the prior-art device.
According to the invention, the above object is achieved by providing an impact armature for a solenoid device, adapted to move and perform a working stroke when said solenoid device is activated, the armature comprising a ferromagnetic armature provided with shoulder means; an effector member made of a non-ferromagnetic material and provided with counter-shoulder means whereby said effector member is engageable by the shoulder means of said armature; characterized in that, in operation, said armature performs a two-phase working stroke, wherein, in a first phase, said armature moves relative to said effector member for a relatively short, predetermined distance while said effector member remains stationary, and, in a second phase, said armature completes its working stroke, said shoulder means engaging said counter-shoulder means, thereby carrying along said effector member.
The invention further provides an impact armature for a solenoid device, adapted to move and perform a working stroke when said solenoid device is activated, said armature comprising a ferromagnetic armature provided with shoulder means; an effector member made of a non-ferromagnetic material and provided with counter-shoulder means whereby said effector member is engageable by the shoulder means of said armature, and a ferromagnetic element affixed to said effector member, characterized in that, in operation, said armature performs a two-phase working stroke, wherein, in a first phase, said armature moves relative to said effector member for a relatively short, predetermined distance while said effector member remains stationary, and, in a second phase, said armature completes its working stroke, said shoulder means engaging said counter-shoulder means, thereby carrying along said effector member and causing it to move a first distance, after which the ferromagnetic element in said effector member, being attracted to said armature, causes said effector member to move an additional distance.